I have a family friend which likes to sleep with a direct connection to earth. This question is purely to do with safety, nothing to do with what you or I or anyone for that matter believes about this practice, just purely about safety.

My initial thoughts were that it is completely safe to plug in to the earth socket of the mains, my initial thoughts were that if any appliance in the house did fail, the electricity would take the path of least resistance into the earth and not into some poor person wearing an earthing bracelet, otherwise aren’t all properly earthed metal devices potentially dangerous?

So I read in a few places that this isn’t necessarily safe, so I was thinking perhaps to put a microamp fuse in series with the bracelets cable. Would this break the circuit in the unfortunate event of a failed device or lightning strike? What would the appropriate current be?

ESD bracelets use a 1M ohm resistor, but for ‘medical earthing’ It doesn’t allow the excess voltage to leave (after measuring it with voltmeter).

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    \$\begingroup\$ I'm not aware of uA fuses. The 1M resistor is the best bet. \$\endgroup\$ – AlmostDone May 16 '18 at 13:03
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    \$\begingroup\$ My immediate feeling was that rolling around with a string attached to an outlet increases the chance of strangling yourself while sleeping much more than it poses a risk of electrocution. \$\endgroup\$ – Arsenal May 16 '18 at 13:24
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    \$\begingroup\$ After measuring what with a voltmeter? Are you saying you actually measured a voltage across a 1 megohm resistor? \$\endgroup\$ – Dave Tweed May 16 '18 at 13:37
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    \$\begingroup\$ That 1 megaohm resistor is all that makes ground straps safe. It isn't the voltage that kills, its the current. Without that resistor, your body is the only thing limiting the current. If you touch something that is at line voltage while wearing a ground strap without resistor, you can be killed. The voltage you are measuring is insignificant, and so is the amount of current it can cause to flow through your body. \$\endgroup\$ – JRE May 16 '18 at 15:44
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    \$\begingroup\$ If your plugging yourself in directly to mains ground you are more likely to receive a shock and die than just sleeping normal. If lightning hit nearby, or a mains fault occurred it could mean shock and possibly death. You need the 1MΩ resistor. \$\endgroup\$ – Voltage Spike May 16 '18 at 17:36

For safety, it's no more dangerous than holding onto an earthed metal appliance. It's safe the vast majority of the time, but there are rare circumstances when the mains earth can become live as a result of a fault in the supply network.

Don't assume that the mains wiring in a house is at 0V. Depending on the supply wiring, it may be several volts above true earth. That's especially true if the public supply is TN-C-S, where the house earth is tapped off the incoming neutral.

If you want real 0V, the only way is to hammer an earth spike into the ground, well away from any mains earth spikes that are already installed.

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  • \$\begingroup\$ Thank you Simon B, so to try and answer my question, would putting a micro amp fuse in series with the wire which connects to earth prevent these “rare circumstances” of the mains earth becoming potentially dangerous. I feel the mega ohm resistor option isn’t a feasible option for what I want to do, I know that it is common practice for ESD bracelets, but I’m not trying to make an ESD bracelet. Also. Bonus question, would a bracelet like this break any sort of health and safety regulations. (In the UK or otherwise). Cheers \$\endgroup\$ – Robert May 16 '18 at 16:12
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    \$\begingroup\$ Ain't no such beast as a "microamp fuse." It would blow every time you touched it. \$\endgroup\$ – JRE May 16 '18 at 16:43
  • \$\begingroup\$ I can't think of any particular safety rules from an electrical point-of-view, since it doesn't actually do anything electrical. As per another's comments above, the bracelet would need some mechanical disconnector so the wearer doesn't get strangled if they roll over in the night. In the UK or elsewhere in Europe, it would have to be CE marked to go on sale, with all that entails. \$\endgroup\$ – Simon B May 17 '18 at 15:41

One dangerous possibility is that when a lightning strikes the earthing network, bed's ground and the wire going to be nodes at very different potentials. No single resistors may help you, because the potential difference is undefined at the first place, don't forget that resistors will also have a voltage rating at some definite humidity level. So, to ensure that the person is always at the local ground potential no matter what, spread some aluminium sheets on the ground (30 cm x 1m on concrete material and have some pressure on it) and connect the bracelet to it, that should provide more than enough grounding for your purpose.

Despite your insist on being the answer on a pure view of electronics, I really have to add my thoughts out of that border. At the first glance, this is a placebo treatment, no matter how and how much you ground the body, it seems that you will never change a millionth of the electrical activity of her hearth. Evidence for anti-thesis is the doctor's responsibility, not mine. Is there any evidence? Did he conducted the most basic rule of science by ruling out psychological effects with some simple experiments?

For the short term, it may be good. For the long term, you are just building a horrible habit making her depended on mains wires. So, for the best compromise, make her believe that it is connected, show it looking like connected, but never connect it. After some time she gets better, explain it to her. These are just my thoughts and recommendations, my apologizes if I used a harsh language, I am not completely in control of this language.

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  • \$\begingroup\$ I understand why you feel this way, and that I have only told you about anecdotal evidence, but this is not pseudoscience. \$\endgroup\$ – Robert May 17 '18 at 22:39
  • \$\begingroup\$ If you are interested, here is a paper on the effects of earthing on blood viscosity, blood viscosity has a great effect on AF. liebertpub.com/doi/pdf/10.1089/acm.2011.0820 \$\endgroup\$ – Robert May 17 '18 at 22:39
  • \$\begingroup\$ And this is a review paper, good read. ncbi.nlm.nih.gov/pmc/articles/PMC3265077 \$\endgroup\$ – Robert May 17 '18 at 22:40
  • \$\begingroup\$ Personally, I have tried sleeping with an earthing bracelet, reluctantly at first I must admit. This is before hearing about the specific health benefits, but boy did I notice a difference. I slept 6 hours and it felt like 8, felt generally better and more energetic throughout the day. \$\endgroup\$ – Robert May 17 '18 at 22:44
  • \$\begingroup\$ Now, I am no biologist, but like I mentioned before, it makes complete sense to me. I’m not sure if you believe in evolution, but it is true that our bodies have evolved to have much more frequent contact with the earth. Electricity plays a major role in our bodies, from our cardiovascular system, our brains, nearly everything. Plastic shoes and concrete jungles prevent this contact with Earth. I’m sure I don’t need to tell you this, but our bodies act like big antennas. Put your finger on an oscilloscope and you’ll see a 50Hz sin wave (In the UK that is) \$\endgroup\$ – Robert May 17 '18 at 22:49

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